Abstract

Objective: We examined the effects of gait training using an original footpad-type locomotion interface named GaitMaster for chronic stroke patients.

Method: Ten chronic hemiparetic patients after stroke participated. The subjects were divided randomly into two groups (n=5 each). Group A subjects followed an ‘intervention phase’ and then a ‘non-intervention phase’, and group B subjects followed the ‘non-intervention phase’ and then the ‘intervention phase.’ In the intervention phase, the subjects underwent twelve 20-min sessions of gait training using the Gait Master. In the non-intervention phase, they performed the same typical rehabilitation or exercise they had been doing before beginning their anticipation in the study.

Main Outcome Measures: We measured the subjects’ gait speed and the isometric muscle strength of hip flexion and extension once a week or after every three Gait Master training sessions.

Results: No significant differences were observed in the clinical data at baseline between the groups. The maximum gait speed improved significantly in the intervention phase compared to the non-intervention phase (p<0.05). Muscle strength in paretic hip flexion (p<0.05), non-paretic hip flexion (p<0.05), and paretic hip extension (p<0.05) improved significantly after the intervention phase compared to the non-intervention phase.

Conclusions: These results suggest that gait training using the Gait Master can improve gait ability and the muscle strength of both paretic hip flexion and extension, and that gait rehabilitation using the Gait Master will be effective for chronic stroke patients.

Gait rehabilitation has changed from traditional unaffected sidemuscle
strength enhancement, brace therapy, and neurophysiological
approaches such as the Bobath approach [1] to a task-specific
approach. Body weight-support treadmill training is representative of
task-specific approaches to gait rehabilitation. In body weight-support
treadmill training, which was developed by Finch et al., the subject is
fitted with harness and performs treadmill training [2]. Body weightsupport
treadmill training is based on the theoretical concept that
a central pattern generator can be facilitated [3,4]. Since Hesse et
al. reported improved gait ability by body weight-support treadmill
training in stroke patients in 1994 [5], many body weight-support
treadmill training-based studies have been conducted, mainly in
stroke patients [6-10]. These studies found that repetitive movement
and hip extension movement are important aspects of body weightsupport
treadmill training [11,12], and therefore, support by physical
therapists is indispensable for body weight-support treadmill training,
although physical therapists’ adoption of this method increases their
burden.

To address this problem, robotic applications such as Lokomat
[13,14] and Gait Trainer [15,16] were developed to help patients swing
their lower limbs. Werner et al. compared the Gait Trainer with
body weight-support treadmill training and reported that patients
in both groups improved their gait ability, walking velocity, and
other motor functions considerably during the treatment period;
they also found that Gait Trainer therapy required less therapeutic
assistance than treadmill training [17]. Mayr et al. compared Lokomat with conventional gait rehabilitation, and they found significant
improvement in function during a 6-week period of Lokomat
training, indicating that functional recovery depends on intensive
and longer training periods [18]. A systematic review showed that
electromechanically assisted training was effective at improving gait
ability after stroke [19]; however, the review also noted some specific
questions to be addressed by further research, including the optimal
frequency and duration of electromechanically assisted gait training,
the initiation timing after stroke, and the high cost of the machines
[20]. Other studies showed that conventional gait rehabilitation has
additional benefits compared to electromechanically assisted training
[21,22].

We have developed a footpad-type, small-sized and low-priced
locomotion interface named the Gait Master- which has footpads
with two degrees of freedom for each lower limb- as a training
system to enable patients to swing their lower limbs efficiently [23]. Gait movement on a Gait Master is a passive movement in which the
footpads move the patient’s feet back and forth and up and down
independently of the patient’s will. The movements of the Gait Master
footpads are realized with chain-drive mechanisms in Gait Master2
[24], ball-screw mechanisms in GaitMaster3 [25], and slider-crank
mechanisms in GaitMaster4 (Figure 1) [26].

GaitMaster4 is 1.59 m long and 1.16 m wide, weighs 80 kg, and is
going to be commercialized below $60,000 dollars (USD). The Gait
Master consists of two slider cranks for moving the footpads back
and forth, two ball-screw actuators for moving the footpads up and
down, and a computer for controlling their movements. No body
weight support devices are needed. The trajectories of the Gait Master
footpads are based on a healthy individual’s gait trajectory, which
is prerecorded with a motion capture device. The trajectory can be
scaled to any size and cycle in accord with the patient’s physical size
and condition. As a result, patients can do repetitive exercise and hip
extension exercise. Since the Gait Master is controlled by computer,
the gait trajectories and gait speed can be easily changed. Moreover,
because the Gait Master moves the lower limbs, a physical therapist
can support the trunk of the patient easily.

We previously reported a feasibility study in which we found that
gait ability in chronic patients was improved after twelve 20-min Gait
Master sessions [27]. Here, we show improvement pattern of muscle
strength and gait ability using the Gait Master4.

Methods

Subjects

As we could not obtain the data of muscle strengths in two
subjects among the patients reported previously [27], the present
populations were 10 chronic-stroke hemiparetic patients (9 men and
1 woman) with a mean age of 59.9 ± 8.7 years and a mean post-stroke
interval of 65.5 ± 51.8 months. Nine patients were right hemiparetic
and 1 was left hemiparetic; the causes of stroke were ischemia (4 cases)
and hemorrhage (6 cases). The inclusion criteria were (1) first-time
stroke, (2) more than 6 months’ passage since stroke onset, (3) slight
to moderate motor deficit (Brunnstrom recovery stages III–VI), and
(4) ambulatory ability with or without any walking aids. The exclusion
criteria were (1) a higher-brain function disorder or cognitive deficit
affecting the ability to understand and describe symptoms (<24 on the
Mini-Mental State Examination), (2) severe heart disorder affecting
gait movement intensity, and (3) severe bone or joint disease affecting
gait movement.

This study was approved by the Tsukuba Memorial Hospital
Ethics Committee, and all subjects or their legal representatives gave
their written informed consent to participate in the study.

Study protocol

The subjects were divided randomly by a computer into two
groups. The group A subjects followed an ‘intervention phase’ and
then a ‘non-intervention phase,’ whereas group B subjects followed the
‘non-intervention phase’ first and then the ‘intervention phase.’ There
was no break between the phases. The intervention phase consisted
of the baseline, Gait Master training (GMT), and a follow-up, and
the non-intervention phase consisted of the baseline, non-training
(NT), and a follow-up. In the intervention phase, after a 4-week
baseline period, the subject performed gait training using the Gait,
Master4 two or three times a week, for a total of 12 GMT sessions,
followed by 4 weeks of follow-up. In the non-intervention phase, the
subject performed the baseline, NT, and follow-up, with each of these
segments lasting 4 weeks (Figure 2).

Therapy on the gait master

The Gait Master4 was developed by the Department of Intelligent
Interaction Technologies, Graduate School of Systems and Information
Engineering, University of Tsukuba. The details of this device are
described elsewhere [25]. In the present study, the conditions of gait
training using the Gait Master4 were as follows: (a) gait training time
was 20 min once a day, (b) the gait speed was set as fast as possible,
with the target being double the subject’s comfortable gait speed, (c)
the subject could use gait orthosis, and (d) the subject was able to grip
the Gait Master4 handrail. The gait speed, stride, and foot clearance
were controlled in accord with the subject’s condition.

During the gait training, the subject’s body movement and lower
limb movement were supported by a physical therapist as needed. All
subjects were monitored continually with electrocardiography and a
sphygmomanometer. During the study period, the subjects continued
the same rehabilitation or exercise regimens they were doing before
the study began.

Assessment

The main outcome measures were the isometric muscle strengths
of hip flexion and extension and the maximum gait speed. In the
intervention phase, we measured each of this parameter once a week
at both baseline and follow-up, and after every three GMT sessions. In
the non-intervention phase, we measured the same parameters once a
week during baseline, non-training, and follow-up.

For the assessment of gait speed, the subject walked 10 m on
the ground at maximum speed. We measured the gait speed of
three attempts by the subject and used the best time as the final
measurement. The subjects could use their same walking aids (if any)
throughout all measurements. A therapist supported the subjects as
necessary.

For the assessment of muscle strength, we used a hand-held
dynamometer (μtas-MF01, Anima Corp., Tokyo) and measured the
isometric contraction muscle strength of hip flexion and extension
as lower-limb muscle strength. We measured the hip flexion with
the subject in the sitting position and the hip extension in the supine
position. We measured the maximum isometric contraction muscle
strength for 10-sec periods. We locked a pressure sensor to a belt that
each subject wore around the limb to record the maximum power. We
used the higher of two strength readings.

Statistical analysis

For muscle strength, and gait speed, we calculated the change
from the mean baseline value. We assumed measurement number 8 in figure 2 (M8) as a representative measurement for ‘after GMT’ or
‘after NT,’ and we used measurement number 12 in figure 2 (M12)
as a representative of the follow-up. The Friedman test was used to
compare the values within the intervention phase and the nonintervention
phase, respectively. The Mann-Whitney U-test was
used to compare the measurements at M8 and M12 between the
intervention phase and the non-intervention phase and to compare
the characteristics between groups A and B. Correlations of muscle
strength and gait speed after GMT were calculated using Pearson’s
correlation coefficient. All statistical analyses were performed using
SPSS (Version 20.0). Significance was set at p<0.05.

Results

No significant differences were observed in the clinical data,
initial muscle strength, and initial gait speed at the study onset
between groups A and B (Table 1).

On the Gait Master4, three of the subjects required the help of a
physical therapist to control the trunk and knee at study onset, and
the other seven subjects did not require this help.

Figure 3 shows the changes in maximum gait speed. During the intervention phase, there was a significant increase in gait speed
(Friedman test, p=0.006), whereas during the non-intervention
phase, there was no significant increase in gait speed (Friedman
test, p=0.905). We found a significant difference in the change in
maximum gait speed at both M8 and M12 between the intervention
and non-intervention phases (M8: p=0.002; M12: p=0.035).

Figure 5 shows the correlations between muscle strengths and gait speed and between the changes of muscle strength and the change of
gait speed; no significant correlations were revealed.

Discussion

In the present study, improvements in lower-limb muscle strength
and gait speed were observed when the Gait Master- a footpad-type,
small-sized and inexpensive locomotion interface !—! was used for
the gait training of chronic stroke patients. The results suggest that
the Gait Master is effective for improving both muscle strength in the
paretic limbs and gait ability.

Previous studies reported that improvement of gait ability is
correlated with improvement of muscle strength of the hip flexion
and extension in paretic limbs [28,29]. In the present study, significant
improvements of gait speed and muscle strength of hip flexion
and extension were observed after GMT, but improvement of gait
speed and muscle strength were not significantly correlated. In gait
training using gait devices, hip extension seems to be important for
the activation of central pattern generator to improve gait ability
[30]. Additionally, recent studies reported that improvement of gait
ability depended on the high-profile plasticity of the brain caused by
repetitive movement, constrained movement, and pelvic assist during
gait movement [30-33]. Therefore, the improvement of gait ability by
the Gait Master training might be due to reorganization of the neural
network and/or to the improvement of muscle strengths. In light of the present results and the findings described above, we propose that
the Gait Master may be useful for chronic stroke patients, because
uniform repetitive gait movement, constrained gait movement, pelvic
rotation, and hip extension and flexion are characteristic gait-like
movements achieved with the Gait Master.

It is notable that the present subjects’ muscle strengths were
significantly improved after BMC Nursing of only 12 training sessions,
since according to National Strength and Conditioning Association
(NSCA) Guidelines, strength training should be implemented for 9 to
20 weeks to produce optimal strength gains. We also found that gait
speeds were improved after 12 sessions of Gait Master intervention,
whereas previous studies using other gait devices required 6 to 8
weeks for improvement [6,7,9,10,17,18]. Our results suggest that Gait
Master4 might be faster at rehabilitating gait in post-stroke patients
compared to other devices.

In conventional gait rehabilitation for stroke patients, a physical
therapist can assist only one stroke patient at a time, and he or she may
have difficulty helping a patient move the lower limbs and trunk at
the same time, or difficulty assisting with long rehabilitation sessions.
Similarly, the simultaneous efforts of two or three physical therapists
are appropriate for the safe gait rehabilitation of a single patient
using body weight-support treadmill training. In the present study,
in contrast, the Gait Master made gait rehabilitation achievable with
little or no assistance from a physical therapist. Since the gait-like movement produced with the Gait Master is controlled by a computer,
the physical therapist is free to help the patient move his or her trunk
and lower limbs, thus enabling long rehabilitation sessions.

These findings indicate that gait rehabilitation using the Gait
Master can not only provide a more effective gait rehabilitation
environment for stroke patients but can also reduce the burden on
physical therapists. Because the present subjects’ gait rehabilitation
using the Gait Master showed quick improvements, we propose that
the Gait Master can provide a new approach for a short-time intensive
model for chronic stroke patients.

In conclusion, gait rehabilitation using the Gait Master improved
gait ability and the strength of both hip extension and flexion in
chronic stroke patients. Using the Gait Master, patients can perform
gait exercises with little support from a physical therapist. In addition,
the Gait Master requires fewer physical therapists than body weightsupport
treadmill training. We therefore feel that gait rehabilitation
using the Gait Master is effective training for chronic stroke patients.
Its main advantages are its characteristic gait-like movement,
the reduced effort on the part of physical therapists, its small size
and its reasonable cost compared with other electromechanically
assisted devices (e.g., the Lokomat is 4,000 dollars). Further studies
are warranted to compare gait rehabilitation using the Gait Master
with conventional gait rehabilitation and with body weight-support
treadmill training and other electromechanically assisted devices.

Acknowledgements

We thank the volunteers and the hemiparetic patients for their participation in this study, and Dr. Susumu Koseki and the rehabilitation staff of Tsukuba
Memorial Hospital for the data collection.